Re: disk speed regression kernel 2.6.29 and after

[Robert Hancock <hancockrwd@gmail.com>]

On 09/23/2009 06:08 AM, will wrote:
> I had been using an old 2.6.22 kernel on my machine, and I often backup
> one partition of my main hard drive to a partition on a second hard
> drive. The main hard drive is sata 640 gigs, and the second is a pata
> 320 gig. copying this partition from one drive to the other with dd
> takes about 3 minutes and 30 seconds. When I installed kernel 2.6.30,
> and 2.6.31, the time took 9 minutes and 20 seconds. I decided to go to
> the trouble of compiling all the kernels between, and kernels
> 2.6.22-2.6.28 all do the operation in about 3 minutes and 30 seconds.
> 2.6.29- newer all take about 9 minutes and 20 seconds. The partition is
> 16 gigs. each drive seems to be as fast as before otherwise, it's just
> much slower copying from one drive to another, which I do very often.
> This is an nforce 3 based motherboard, amd southbridge, i think, with 4
> gigs of ram, athlon 64x2. 32 bit kernel. has anyone heard of this problem?
> I currently have 3 hard drives hooked up.
> a 200 gig on a promise controller,
> a 320 gig on the amd pata?
> a 640 sata on the nv i think.
> The motherboard is a Asrock-AM2NF3-VSTA
> copying this partition with dd or cat or schily's dd between any of these 3
> different hard drives takes different times depending on the speed of
> the drive with
> kernels 2.6.22-2.6.28, but takes about 9 minutes and 30 seconds on any
> of the drives
> with the kernels 2.6.29 and after.
> Please cc me with any followups or anything. thanks.

Can you post the dmesg output from bootup on both the good and bad kernels?